Particle Production of Hg and Ga Target at 15to2T5m (compared with C target at 20to2T5m) at 6.75 GeV X. Ding, UCLA Target Studies June 5, 2014 6/5/14 1

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Target Setting

Hg and Ga target with 15to2T5m Configuration (no resistive copper) and Fieldmap (15T  2T); • • • Carbon target with 20to2T5m Configuration (with resistive copper) and Fieldmap (20T  2T); Code: MARS15(2014) with ICEM 4 = 1; Proton beam: 6.75 GeV (KE) and launched at z = -100 cm, Focal beam with waist at z= 0 m and emittance of 5 μm; • Production Collection: (50 m downstream, 40 MeV < KE < 180 MeV).

• BR/TR=0.3 for Hg and Ga; BR/TR=0.25 for Carbon; • ENRG 1 = 6.75, 2 = 0.02, 3 = 0.3, 4 = 0.01, 5 = 0.05, 6 = 0.01, 7 = 0.01 (Energy card setting) 6/5/14 2

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15to2T5m Fieldmap

(along SC axis) 3

• • •

Optimized Target Parameters And Yield Comparison

(1000,000 events) Carbon (length: 80 cm, target radius: 0.8 cm, beam radius: 0.2 cm, beam angle: 65 mrad, crossing angle: 0 mrad ) at 20to2T5m; Production: 120842 Hg (target radius: 0.54 cm, beam radius: 0.162 cm, beam angle: 95 mrad, crossing angle: 26 mrad ) at 15to2T5m; Production: 140856 (+16.6% higher than C) Ga (target radius: 0.60 cm, beam radius: 0.18 cm, beam angle: 70 mrad; crossing angle: 16 mrad ) at 15to2T5m; Production: 135470 (+12.1% higher than C) 6/5/14 4

Carbon target, 20to2T5m

(Extension of maximum target radius from 1.6 cm to 2.4 cm) 20to2T5m Configuration; Target length: 80 cm; Beam angle: 65 mrad; Beam/Target crossing angle: 0 mrad; TR/BR=4; 6/5/14 5

Carbon target, 20to2T5m (Cont’d)

Target radius, cm

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

Yield per proton per GeV

0.0178778

0.0174818

0.0169881

0.0164227

0.0157262

0.0150353

0.0144062

0.0139147

0.0134181

Difference

0%

-2.2% -5% -8.1%

-12%

-15.9% -19.4% -22.2%

-24.9%

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